From: Gerd Hoffmann <kraxel@suse.de>
To: "xen-devel >> Xen devel list" <xen-devel@lists.xensource.com>
Subject: [patch 2/3] Introduce new "online" node for backend drivers.
Date: Thu, 31 Aug 2006 09:41:26 +0200 [thread overview]
Message-ID: <44F692A6.70603@suse.de> (raw)
[-- Attachment #1: Type: text/plain, Size: 642 bytes --]
Hi,
This patch introduces a new "online" node for backend drivers.
Driver changes: Make backend drivers check it when entering Closed
state, only unregister devices when the "online" node is either "0" or
not present. The later maintains backward compatibility.
Tools changes: Update "online" node when creating and hot-unplugging
devices.
Background: When kexec'ing a new kernel, the old kernel's frontend
driver will shutdown, but the backend device should *NOT* disappear
due to that, so the new kernel instance can reconnect.
please apply,
Gerd
--
Gerd Hoffmann <kraxel@suse.de>
http://www.suse.de/~kraxel/julika-dora.jpeg
[-- Attachment #2: linux-backend-online.diff --]
[-- Type: text/x-patch, Size: 8774 bytes --]
Introduce new "online" node for backend drivers.
Driver changes: Make backend drivers check it when entering Closed
state, only unregister devices when the "online" node is either "0" or
not present. The later maintains backward compatibility.
Tools changes: Update "online" node when creating and hot-unplugging
devices.
Background: When kexec'ing a new kernel, the old kernel's frontend
driver will shutdown, but the backend device should *NOT* disappear
due to that, so the new kernel instance can reconnect.
Signed-off-by: Gerd Hoffmann <kraxel@suse.de>
---
linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c | 10 +++--
linux-2.6-xen-sparse/drivers/xen/blktap/common.h | 1
linux-2.6-xen-sparse/drivers/xen/blktap/interface.c | 19 ++++++----
linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c | 16 +++++++-
linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c | 10 +++--
linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_backend_client.c | 11 +++++
linux-2.6-xen-sparse/include/xen/xenbus.h | 1
tools/python/xen/xend/server/DevController.py | 6 ++-
8 files changed, 58 insertions(+), 16 deletions(-)
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
@@ -301,11 +301,11 @@ static void frontend_changed(struct xenb
struct backend_info *be = dev->dev.driver_data;
int err;
- DPRINTK("");
+ DPRINTK("%s", xenbus_strstate(frontend_state));
switch (frontend_state) {
case XenbusStateInitialising:
- if (dev->state == XenbusStateClosing) {
+ if (dev->state == XenbusStateClosed) {
printk("%s: %s: prepare for reconnect\n",
__FUNCTION__, dev->nodename);
xenbus_switch_state(dev, XenbusStateInitWait);
@@ -331,8 +331,12 @@ static void frontend_changed(struct xenb
xenbus_switch_state(dev, XenbusStateClosing);
break;
- case XenbusStateUnknown:
case XenbusStateClosed:
+ xenbus_switch_state(dev, XenbusStateClosed);
+ if (xenbus_dev_is_online(dev))
+ break;
+ /* fall through if not online */
+ case XenbusStateUnknown:
device_unregister(&dev->dev);
break;
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c
@@ -228,13 +228,13 @@ static void frontend_changed(struct xenb
{
struct backend_info *be = dev->dev.driver_data;
- DPRINTK("");
+ DPRINTK("%s", xenbus_strstate(frontend_state));
be->frontend_state = frontend_state;
switch (frontend_state) {
case XenbusStateInitialising:
- if (dev->state == XenbusStateClosing) {
+ if (dev->state == XenbusStateClosed) {
printk("%s: %s: prepare for reconnect\n",
__FUNCTION__, dev->nodename);
if (be->netif) {
@@ -260,8 +260,12 @@ static void frontend_changed(struct xenb
xenbus_switch_state(dev, XenbusStateClosing);
break;
- case XenbusStateUnknown:
case XenbusStateClosed:
+ xenbus_switch_state(dev, XenbusStateClosed);
+ if (xenbus_dev_is_online(dev))
+ break;
+ /* fall through if not online */
+ case XenbusStateUnknown:
if (be->netif != NULL)
kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
device_unregister(&dev->dev);
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_backend_client.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_backend_client.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_backend_client.c
@@ -132,4 +132,15 @@ int xenbus_unmap_ring(struct xenbus_devi
}
EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
+int xenbus_dev_is_online(struct xenbus_device *dev)
+{
+ int rc, val;
+
+ rc = xenbus_scanf(XBT_NIL, dev->nodename, "online", "%d", &val);
+ if (1 != rc)
+ val = 0; /* no online node present */
+ return val;
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_is_online);
+
MODULE_LICENSE("Dual BSD/GPL");
Index: build-32-unstable-11288/linux-2.6-xen-sparse/include/xen/xenbus.h
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/include/xen/xenbus.h
+++ build-32-unstable-11288/linux-2.6-xen-sparse/include/xen/xenbus.h
@@ -298,5 +298,6 @@ void xenbus_dev_fatal(struct xenbus_devi
int __init xenbus_dev_init(void);
char *xenbus_strstate(enum xenbus_state state);
+int xenbus_dev_is_online(struct xenbus_device *dev);
#endif /* _XEN_XENBUS_H */
Index: build-32-unstable-11288/tools/python/xen/xend/server/DevController.py
===================================================================
--- build-32-unstable-11288.orig/tools/python/xen/xend/server/DevController.py
+++ build-32-unstable-11288/tools/python/xen/xend/server/DevController.py
@@ -207,7 +207,8 @@ class DevController:
devid = int(devid)
- self.writeBackend(devid, 'state', str(xenbusState['Closing']))
+ self.writeBackend(devid, 'state', str(xenbusState['Closing']))
+ self.writeBackend(devid, 'online', "0")
def configurations(self):
@@ -406,7 +407,8 @@ class DevController:
'domain' : self.vm.getName(),
'frontend' : frontpath,
'frontend-id' : "%i" % self.vm.getDomid(),
- 'state' : str(xenbusState['Initialising'])
+ 'state' : str(xenbusState['Initialising']),
+ 'online' : "1"
})
return (backpath, frontpath)
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c
@@ -247,6 +247,11 @@ static void tap_frontend_changed(struct
switch (frontend_state) {
case XenbusStateInitialising:
+ if (dev->state == XenbusStateClosed) {
+ printk("%s: %s: prepare for reconnect\n",
+ __FUNCTION__, dev->nodename);
+ xenbus_switch_state(dev, XenbusStateInitWait);
+ }
break;
case XenbusStateInitialised:
@@ -264,11 +269,20 @@ static void tap_frontend_changed(struct
break;
case XenbusStateClosing:
+ if (be->blkif->xenblkd) {
+ kthread_stop(be->blkif->xenblkd);
+ be->blkif->xenblkd = NULL;
+ }
+ tap_blkif_unmap(be->blkif);
xenbus_switch_state(dev, XenbusStateClosing);
break;
- case XenbusStateUnknown:
case XenbusStateClosed:
+ xenbus_switch_state(dev, XenbusStateClosed);
+ if (xenbus_dev_is_online(dev))
+ break;
+ /* fall through if not online */
+ case XenbusStateUnknown:
device_unregister(&dev->dev);
break;
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/common.h
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/blktap/common.h
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/common.h
@@ -91,6 +91,7 @@ blkif_t *tap_alloc_blkif(domid_t domid);
void tap_blkif_free(blkif_t *blkif);
int tap_blkif_map(blkif_t *blkif, unsigned long shared_page,
unsigned int evtchn);
+void tap_blkif_unmap(blkif_t *blkif);
#define blkif_get(_b) (atomic_inc(&(_b)->refcnt))
#define blkif_put(_b) \
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
@@ -135,20 +135,25 @@ int tap_blkif_map(blkif_t *blkif, unsign
return 0;
}
-void tap_blkif_free(blkif_t *blkif)
+void tap_blkif_unmap(blkif_t *blkif)
{
- atomic_dec(&blkif->refcnt);
- wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
-
- /* Already disconnected? */
- if (blkif->irq)
+ if (blkif->irq) {
unbind_from_irqhandler(blkif->irq, blkif);
-
+ blkif->irq = 0;
+ }
if (blkif->blk_ring.sring) {
unmap_frontend_page(blkif);
free_vm_area(blkif->blk_ring_area);
+ blkif->blk_ring.sring = NULL;
}
+}
+void tap_blkif_free(blkif_t *blkif)
+{
+ atomic_dec(&blkif->refcnt);
+ wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
+
+ tap_blkif_unmap(blkif);
kmem_cache_free(blkif_cachep, blkif);
}
[-- Attachment #3: Type: text/plain, Size: 138 bytes --]
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel
reply other threads:[~2006-08-31 7:41 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=44F692A6.70603@suse.de \
--to=kraxel@suse.de \
--cc=xen-devel@lists.xensource.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.